Set on a prominent cliff overlooking the river, historic Salosel Castle is no longer much to look at above ground. However, the caretaker will gladly show you the impressive Sassanian-era subterranean rooms and water channels. The tour also includes the stables (now a small museum) and a women's weaving workshop. Look for the English sign on Shari'ati St, about 500m northwest of Shahrivar Sq, before Bateni Sq.
Salosel Castle is where Shapur I is said to have imprisoned Roman emperor Valerian. It’s also here that Persians held out for two years against the invading Arab Muslim armies until secret tunnels were revealed to the attackers by a traitor. For centuries Khuzestan was governed from a palace (‘Kushk’) on this site, and an impressive three-storey pyramidal building stood here until the 1920s.